I'm looking for a wired hands-free headset, and most of the ones I've seen here are just headphones (no mic). Anyone have any luck with headphones+mic from third parties?

I've tried buying different ones (from motorola to sony, etc) but they all make a high pitched screeching sound when plugged into the N900... Only the original ones work, and they are falling apart on me...

Is my only option to buy from Nokia?